The present invention relates generally to vehicle control and, more particularly, to an improved assembly for both supporting one or more control handles in a lift truck such that interference with a movable deck or like structure is avoided and linking the control handles to valves for controlling the operation of a carrying assembly forming a part of the lift truck.
In a conventional lift truck, an array of control handles are provided for controlling the flow of hydraulic fluid typically used to raise, rotate, or otherwise move a portion of the carrying or lifting apparatus (i.e., the mast and forks and accompanying structures). These control handles should be conveniently located within the operator compartment for easy, comfortable access. Of course, providing control handles that are securely and reliably linked to the corresponding valve(s) for controlling the flow of hydraulic fluid is also an important consideration, as is minimizing the number of parts required and reducing the overall complexity.
Typically, a lift truck is provided with a compartment covered by a movable deck that carries an operator""s seat. This compartment usually contains components responsible for providing power to the lift truck, including the battery. In such an arrangement, positioning the control handles comfortably within the reach of the operator generally places them immediately over the seat deck or other movable structure forming a part of the lift truck base. As a result of this placement, the control handles create an obstacle to removing the deck for gaining access to the adjacent battery compartment or the like.
In one prior art truck, before the seat deck can be opened to gain access into the battery compartment, a control handle release mechanism must be actuated followed by the manual pivoting of the control handles away from the seat deck. Such an arrangement is disadvantageous as additional time and effort are required to reposition the control handles prior to opening the seat deck. Further, it requires that an operator be positioned on a side of the truck to which the control handles are located when opening the seat deck. Typically, this side of the truck is opposite to the side that is used when exiting or entering the operator""s compartment, resulting in the operator walking around the truck before and/or after opening the seat deck.
In another prior art truck, the control handles, structure which couples the handles to corresponding valves and a front cover, automatically pivot away from the seat deck when the deck is opened. A costly pivoting plate must be provided for mounting the handles, the coupling structure and the front cover. It is also noted that the plate has a low pivot position. Consequently, substantial clearance is required between the floorplate and the front cover, to allow the plate, the control handles, the coupling structure and the front cover to rotate away from the seat deck when the seat deck is raised. This clearance allows the ingress of foreign material onto the hydraulic valves, which is undesirable. Further, the shape of the front cover restricts easy ingress into and egress from the operator""s compartment.
Thus, a need is identified for an improved manner for supporting one or more control handles within the comfortable reach of the operator, while at the same time avoiding the creation of interference with removable structures on the lift truck, such as the deck carrying the operator""s seat.
In accordance with a first aspect of the invention, a control handle support and valve linkage apparatus for mounting adjacent a movable deck on a lift truck is provided. The apparatus includes a first stationary bracket and a second bracket in engagement with the first bracket. At least one control handle assembly is coupled to the second bracket, and preferably positioned for easy access by the lift truck operator when seated in the operator""s compartment. The second bracket is movable relative to the first bracket between a first retracted position and a second non-interfering position, with the second bracket being in the first position when the deck is in a closed position and in the second position when the deck is moved to an open position. Accordingly, when the seat deck is opened, the second bracket simultaneously pivots to move the control handle assemblies out of the way. This simultaneous pivoting action avoids creating any interference between the control handle assemblies and the seat deck as it is lifted. Further, the pivoting action avoids any interference between the handle assemblies and the battery when the battery is lifted for removal.
In one embodiment, the control handle support and valve linkage apparatus includes a spring for biasing the second bracket relative to the first bracket. The biasing force supplied by this spring allows the second bracket to pivot from the first to the second position when the deck is opened. Preferably, the second bracket rotates through an angle from about 15 degrees to about 90 degrees in moving from the first position to the second position, and most preferably through an angle of about 22xc2x0. To provide the desired simultaneous pivoting action and relative movement, the second bracket further comprises a projecting member and the deck includes an actuator. When the deck is moving from the open to the closed position, this actuator engages the projecting member to overcome the spring biasing force and pivot the second bracket to the first position. In a most preferred embodiment, the projecting member is a substantially cylindrical rod and the actuator includes a C-shaped recess for engaging the rod. The deck preferably is at least a portion of a seat deck forming a part of a base portion of the lift truck.
In accordance with a second aspect of the present invention, a control handle support and valve linkage assembly is provided for mounting adjacent to a movable deck on a lift truck having a carrying assembly. The control handle support and valve linkage assembly comprises a first stationary bracket, at least one valve for controlling fluid flow to and away from the carrying assembly on the lift truck, a second bracket engaging the first bracket, at least one control handle assembly coupled to the second bracket, structure for coupling the at least one control handle assembly to the at least one valve, and at least one switch coupled directly to the at least one valve and operable to control fluid flow to the at least one valve. The second bracket is movable relative to the first bracket between a first position when the deck is closed and a second position when the deck is open. Preferably, the coupling structure does not pivot or otherwise move when the second bracket moves between its first and second positions.
Preferably, the control handle support and valve linkage assembly further includes a stationary cover. In one preferred embodiment, the cover has a generally planar outer surface. Advantageously, this planar outer surface does not interfere with the ingress to and egress from the operator""s compartment of the lift truck.
In one embodiment, the second bracket rotates relative to the first bracket through an angle of from about 15 degrees to about 90 degrees in moving from the first position to the second position. The second bracket may also rotate through other angular ranges including all ranges subsumed within the range of from about 15 degrees to about 90 degrees. Also, the coupling structure comprises at least one link and at least one cam. The at least one link is coupled to the at least one control handle assembly and the at least one cam. The at least one cam is further coupled to the at least one valve, which preferably comprises a spool valve.
Most preferably, first and second control handle assemblies are provided as part of the control valve linkage assembly. A spring is also provided for biasing the second bracket relative to the first bracket such that the second bracket pivots from the first position to the second position when the deck is moved to the open position. The second bracket includes a projecting member and the deck further comprises an actuator for engaging the projecting member to pivot the second bracket to the first position when the deck is moved to a closed position. In one particular embodiment, the projecting member is a substantially cylindrical rod and the actuator includes a C-shaped recess for engaging the rod. The deck is a seat deck forming a part of a base portion of the lift truck.